Thermal Stability of Capped Organic Films

To address this problem we have prepared highly crystalline films of the organic semiconductor DIP and capped them with r.f magnetron sputtered aluminium oxide films. 

AI2O3/DIP (filled squares) compared to the roughness (SiOJ of the Al203/Si0 system (open circles). The scaling behaviour of aluminium oxide layers deposited on DIP and on SiO are in good agreement. With permission from Ref [112]. 

Surprisingly, the aluminium oxide/DIP multilayer strueture did not show significant ehanges when heating the sample up to 350 °C. And only around 410 °C, i.e. 210 K above the desorption temperature of uneapped DIP films (on SiOJ the multilayer structure broke down. 

In conclusion, we eould show that the thermal stability of crystalline films of DIP can be strongly enhanced by aluminium oxide encapsulation [113, 114]. The important finding is that the erystallinity of these films could be preserved to temperatures up to 300 K above the desorption temperature of uneapped films. 

We wish to thank the DFG for finaneial support. We would like to aeknowled-ge numerous fruitful interaetions within the DFG foeus program 1121 on orga-nie field effeet transistors. We also thank the synehrotron radiation sourees ESRF (Grenoble), ANKA (Karlsruhe) and BESSY (Berlin) for providing ex-eellent experimental support. 

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